Spark-plug.



L` A. MCDOWELL SPARK PLUG.

APPfLICAUoH mn Nav. 9, w14

1 ,1 96566 .Patented Aug. 29, 1916.

UNITED sTATEs PATENT OFFICE.4

LEWIS A. MCDOWELL, OF LUVERNE, MINNESOTA.

SPARK-PLUG.

To all whom it may concern:

Be it known that I, Lewis ANDREW Mc- DowELL, a citizen of the United States, residing at Luverne, in the county of Rock, State of Minnesota, have invented certain neul and useful Improvements in Spark- Plugs; and I do hereby declare the following to be a` full, clear, and exact description of the invention, such as will enable others skilled inthe art to which it appertains to make and use the same.

This invention relates to a spark plug.

'An object of the invention is kto so construct the device that when the engine makes its compression stroke the gas compressed within the plug is ignited and forced outwardly into the main compression chamber and thus a more powerful explosion is obtained. g A further object of the invention is to so construct the device that the length of the spark may be varied at will.

A further object of the invention is to provide for the removal and replacing' of the upper electrode so that the saine may be cleaned and replaced in such position that the spark between the electrodes will always remain constant.

Av further object of the invention is to prm'de for the locking of the lower electrode in a predetermined position.

A further object of the invention is to make provision in the device for keeping the carbon from short circuiting the plug.

-A Yfurther object of the invention is to so construct and arrange the electrodes that irrespective of the warping causedby the heat within the cylinder the movable electrode will be arranged above the stationary electrode so that the sparkwill not be distorted.

With these and other objects in view, such as will appear as the description progresses, my invention comprises the combinationl and arrangement of parts as set forth in and falling within the scope of the4 appended claims.

Referring to the drawing: Figure 1 is a longitudinal sectional view of my device. Fig. 2'is an elevational view of the inner core or insulator; Fig. 3 is a detail of the stationary electrode carrier. Fig. 4 is a sectional view on line 4-4 of Fig. 1.

Referring to the drawing wherein like Specification of Letters Patent.

threaded on its lower end, as at 6 Patented Aug. 29, 1916.

Application led November 9, 1914. Serial No. 871,140.

parts are indicated by like characters throughout the several views My device comprises a shell 5`which is S0 that it may be.readily screwed into the proper. opening in a combustion cylinder. This shell 5 has a hole 7 extending therethrough,which hole is threaded at its lower'end, as at 8.

Detachably connected with the lower end of the shell 5 on the screw threads 8.is a split collar 9,A the formation of which is shown in Fig. 3. Depending from this collar is a U-shaped member 10 having an upwardly extending electrode 11 mounted in thebight vportion thereof. This collar'is split in order that after it has been engaged with the threads 8 it will bind on the said threads and thus the rotation of the electrode 11 will be prevented, it being of course understood that the collar will possess a certain amount of resiliency to cause the binding action.

In order that an upper electrode may be properl mounted with relation to the lower electro e 11, I have enlargedthe. vhole 7 adjacent the upper end of the shell 5 so that a shoulder y12 is rovided on which is a packing ring 13. esting on this packing ring and extending downwardly into the hole is an insulating barrel 14 'which is in spaced relation to the inner wall of the said shell 5. This barrel has an upwardly extending shank ortion 15 which is likewise in spaced re ation to the shell. This barrel is maintained in proper position by a )am nut 16 pressed on a shoulder 17 on the said barrel but being insulated therefrom by suitable material 18.

' Extending longitudinally through this barrel 15 is a hole 19. The lower end of this hole is enlarged, as at 20, and is of-triangular formation.y The hole is still further enlarged adjacent the lower end thereof forming a chamber 21 and a vshoulder 22 between the chamber and the portion 20.

Removably mounted in this liole 19 is a rod 23 having an enlarged triangular portion 24 thereon, which fits into the portion 20 of the hole 19 but is of slightly lesser diameter. A packing material 25 is placed in this portion 20 so as to prevent the escape of gases from the cylinder upwardly through'the hole 19 around the rod-23. Be-` low this triangular portion 24 is a collar 26 adjusting nut 29 by means of which nut and cap the distance between the electrodes may be varied. v

v`r zimr'c uiting the device, I have provided a cirvIn order that carbon' deposited may be prevented from caking entirely vabout the outer surface of vthe barrel 14 and thusshort 'cular grooven30- a`djacent the lower end "thereof in which groove is mounted a split Collar 31, the said collar being mounted so that it may have rotative movement with relation to the barrel in the said groove and also vertical up and down movement with relation to the barrel, thus etlectivelypref venting the caking of Athe carbon in a continuous sheet between the said barrel and Athe shell 5, the motion being caused by the vibration of the' engine. Y

From the foregoing description it may be `readily observed that should the lower electrode become calred with carbon after continued use, the said electrode may Abe bodily removed by unscrewing the collar-9, and it may then be replacedand held in such position because of the factthat it is split and resilient which causes the said collar to grip A. this portion of the shell 5. Should it beV desirable to remove the upper electrode for any reason whatsoever this may beaccomplished by unscrewing the nut 16 and lifting the electrode together with the barrel 1.4 bodily from the shell 5, this electrode may then be replaced and the shoulder` thereon will contact with the shoulder' 'l2 in the shell 5 to positively' position the. electrode point 27 in the same relation to the electrode 111 that it bore before being displaced.

Furthermore I have provided a spark vplug wherein the possibilityof short circuiting being causedby the carbon deposit will be obviated by the use of a loosely mounted collar on' the barrel which will prevent the formation of a continuous sheet of carbon between the .barrel and the shell, furthermore I have so constructed'the device that should the movable electrode bccome warped by the'action of the heat in the cylinders the spark-will not be distorted i by the said warping inasmuch as a portion of the electrode will -be kept in alinement with the portion of thestationary electrode.`

' dinally extending hole1 therein, an -insulat. ing barrel extending into the shell and'inv spaced rela-tion to the. wall thereof, the'said barrel'having an annular recess encirclingthe same a d]acent its lower end, electrodesY located below the insulatingbarrel, randf a split col-lar, ofslightly less width thanthe V recess, mounted in the recess' andadapted to Vmove'upon thevibration fo the; 'plug to prevent' the forming of a continuous sheet of carbon on the face of the barreL'the said collarbcing rectangular in 'cross sectionwherebyjshja'rp 'edges are provided and bef ing ofgreater' inside'diameter than the diameter of ltheportion of. the insulating barrel which it encircles whereby upon the v1- bration of the ,plug and the movement of the collar, the axis of the latter will assume an angular position with relation to the aXlS of the barrel and the sharp edgesV of the collar will engage the adjacent portion ot the ,tace o the barrel and cut the carbon therefrom. Y

In testimony ,-Whcleof, I alix my signature, in the presencev 'of two witnesses LEY VIS A. MCDOVVELL.

l/Vitnesses:

C. J. MARTIN, J. VV.McDo\vi-:LL. 

